Performance indexes of a breaker serving as an important element among low-voltage electrical apparatuses can restrain development of an industry. In the age of continuous development and growth of new energy, particularly dramatic development of the photovoltaic power generation field, a system voltage of the breaker may be up to 800V, and highland capacity reduction also needs to be considered when the breaker is used on a highland. A multibreak series technology was formerly used to meet the high-voltage demand of a photovoltaic system, but it still has unsolved problems of large volume, high power consumption, great difficulty of construction and installation, etc. The previous application No. 201110005730.7 entitled “Multibreak Breaker” and No. 201020586389.X entitled “Multibreak Plastic Housing Type Breaker” propose a preset wiring technology to solve the problem of construction and installation, but they fails to solve the problems of large volume and high power consumption essentially. An arc extinguishing problem needs to be solved at first if it is desired to replace a multibreak series breaker by a two-electrode breaker to meet photovoltaic application. It is well known that the basic principle of direct current arc extinguishing is arc elongation and arc cooling.
Chinese invention patent application publication CN 101546681 B discloses a breaker capable of protecting a movable contact and facilitating entrance of an arc into an arc extinguishing chamber, of which the primary technical means is as follows: an arc ignition plate electrically connected with a release at a tail portion of the movable contact is provided on an upper end of the arc extinguishing chamber, and an insulating cover is also arranged to avoid a short circuit between the arc and a side of the arc ignition plate near the tail portion of the movable contact, as the arc ignition plate has to penetrate through a region generating an arc when the breaker is disconnected. Due to the arrangement of this arc ignition plate, the arc generated when the movable contact is opened in the case of short circuit can easily skip from the movable contact to the arc ignition plate and enter the arc extinguishing chamber, so that ablative loss of the movable contact is reduced and the arc can easily enter the arc extinguishing chamber. In this technical solution, however, if it is desired that the arc can very easily skip from the movable contact to the arc ignition plate, the resistance of the arc ignition plate needs to be smaller than the parallel resistance of the movable contact and the arc ignition plate, while this is theoretically impossible. Further, one end of the arc ignition plate needs to be electrically connected with the release at the tail portion of the movable contact, the other end of the arc ignition plate shall be arranged above the arc extinguishing chamber, and meanwhile an insulation cover must be arranged for insulation of the arc ignition plate. Therefore, the structure of the arc ignition plate is too complicated, resulting in that assembly of the breaker becomes complicated. Furthermore, the invention is favorable for skipping of the arc from the movable contact to the arc ignition plate and entrance of arc into the arc extinguishing chamber, but has very little effect on elongation of the arc, and thus it is obvious that the effect on arc extinguishing and improvement of working voltage of the breaker is obviously not enough.